For the classical Greek philosophers, the cultivation of human rationality is a central ingredient of education andedification. But notions of reason and rationality have received various interpretations. A plurality of interpretations directs our attention to the general philosophical queries, What is rationality? and Why should we be rational? In this paper, I consider only briefly the first question by distinguishing three aspects of rationality in Section 2. Then I shall use, in Section 3, these three notions to give nine reformulations of the puzzling question ‘Is it rational to be rational?’. My main task is concerned with the analysis of the relevant questions, not in their answers. I hope this approach helps us to understand in a clearer way the nature and importance of human rationality